Stream: t-compiler/const-eval

Topic: Remove `const_fn` feature gate


oli (Jan 23 2020 at 15:01, on Zulip):

There's also the task of deprecating the current semantics for unadorned bounds in const fn and directing people to use ?const. I had mentioned that it would be possible to have #![feature(const_fn)] preserve the existing semantics for trait bounds at the cost of slightly increased complexity in the const checker. I would have liked to have removed qualify_min_const_fn entirely by this point; it would have made the back-compat idea easier since #![feature(const_fn)] wouldn't serve double duty. Since that pass still exists, I think we should not try to do the back-compat thing.

oli (Jan 23 2020 at 15:01, on Zulip):

Yea that's an annoying situation

oli (Jan 23 2020 at 15:02, on Zulip):

Could we do an intermediate step and keep qualify_min_const_fn but just run it on all const fn now

oli (Jan 23 2020 at 15:04, on Zulip):

Then you could make the if feature_gate(const_trait_bound_opt_out) check be if feature_gate(const_trait_bound_opt_out) || feature_gate(const_fn) and remove all other uses of the const fn feature gate in rustc

oli (Jan 23 2020 at 15:05, on Zulip):

I don't remember if we got rid of the const_fn check in constness.rs yet

Last update: Jul 02 2020 at 19:25UTC